How can I make the neck of this desk light?
Modeling

Create a bezier curve tracing the neck of the lamp. Model a small part of the neck and array it using the bezier curve as a Fit Type. This will repeat the part till it fits the length of the curve.



Then using Curve Deform modifier, deform the output over the curve.



Now scale the object and apply the scale to get the required amount of repetitions.

Procedural Shading

If you want to implement the bumps in shading stage. Solidify the curve and and enable Use UV For Mapping.



Then for the material, use the $x$ component of the UV to compute strips like pattern where the value $20$ controls the number of repetitions, $0.17$ controls the width of engraving and $0.2$ controls the relative slope of the transition.



You can now use this as bump of displacement for the material.